In the FTTH application scenario, the 2/4/8/16/32/64-way optical splitter is suitable for the plc process. The 3/10/12-way optical splitter is suitable for the FBT process. To ensure the convenience of operation and maintenance, reduce the cost of network maintenance and transformation. We suggest selecting full-band optical splitter (the applicable wavelength is 1260~1650nm). We should also ensure the optical performance of the fiber optic connectors in the beamsplitter. The working ambient temperature of the optical splitter is also very important. It should be determined according to the environment of the usage scenario.
Next, we will explain in detail how to select and use a plug-in plc splitter.
1. Classification of the production process of the optical splitter.
There are two types of optical splitters on the market: FBT and PLC.
(1) FBT splitter
The process of making FBT splitter takes a long time. Two (or more than two) bare fibers are heated and melted at high temperatures and stretched to both sides. Finally, a special waveguide structure of a “double cone” is formed in the heating area. According to the different light-splitting ratios required. The length and twisting angle of the optical fiber is controlled. After forming, the taper area is fixed and packaged with curing glue and installed on the quartz substrate.
The optical splitter produced by the FBT process can achieve any splitting ratio. But, in actual use, the thermal expansion coefficients of the quartz substrate, stainless steel tube, optical fiber, and curing glue are inconsistent. The degree of thermal expansion and contraction is also inconsistent with the change in temperature, which leads to damage to the optical splitter. With the advancement of FTTH, there are more and more scenarios where the optical splitter is placed in the wild, and the ambient temperature varies, so the damage rate of the FBT (fused taper) optical splitter is high.
(2) PLC splitter
PLC splitter is processed and manufactured by new semiconductor processes. Such as photolithography and development. Since the optical waveguide array and the branch. Function disintegrated on one chip, and the multi-channel fiber arrays at the input end and the output end are coupled and packaged at both ends of the chip. They are less affected by the ambient temperature.
The advantages of PLC splitter are very obvious.
●The loss of each transmission window of 1310nm, 1490nm, and 1550nm is the same.
●The consistency of each port is good; the structure is small and suitable for installation in various junction boxes.
●There are many branch channels for a single device, It can reach 64 or 128 channels.
●The multi-channel cost is low, and the more the number of branches, the more obvious the cost advantage.
The PLC splitter also has some shortcomings. Due to the high production process requirements, the product cost is high, especially with the small number of splitters.
2. Plug-in plc splitter
The plug-in plc splitter adopts the standard shell to package the optical splitter, of which the 1-slot type is the basic type. The external dimension is 130mm×100mm×25mm, the maximum is 1:8 when using SC type connector, and the maximum is 1:16 when using LC type connector. The thickness of the 2-slot type is doubled, and the installation takes up 2 slots.
Since the plug-in optical splitter comes with an optical fiber adapter. It is suitable for installation in a wiring cabinet or box such as a non-jumper optical cable junction box. Selecting LC-type connectors and fiber optic adapters can double the capacity under the same volume. Therefore, when the installation location is tight. It is recommended to use LC-type connectors and optical fiber adapters
(1) Selection of the splitting ratio of the plug-in optical splitter
We have conducted a statistical analysis on the plc splitters that have been used for many years in FTTH construction. We found that the optical splitters used are mainly concentrated in 2-point, 3-point, 4-point, 8-point, 10-level, 12-level, and 16-level Equal splitting. Non-uniform splitters are used less, and 25%:75% type non-uniform splitters can be used.
Since the PLC process is used. The optical splitter must be uniformly split. The number of optical splits must be a power of 2, so some specifications of the optical splitter use the FBT process. According to the actual needs of the construction of the cable television, broadband multimedia integrated information network. It is determined that the 2, 4, 8, 16, 32, and 64-way equalized optical splitters use PLC technology. And the 3, 10, and 12 equalized optical splitters and 25%:75% type non-uniform optical splitter adopts the FBT process.
(2) Working wavelength
According to the working window covered by device performance. Optical splitters are divided into single/double/three/full-window broadband splitters. The two-way network construction of cable TV is divided into two structures. Single-fiber three-wave and double-fiber three-wave structures.
Three wavelengths of 1310nm, 1490nm, and 1550nm are required. Generally, 1310nm and 1490nm constitute the upstream and downstream channels of data transmission. 1550nm is used for TV signal transmission. The FTTH network usually selects the optical splitter of the whole band (applicable wavelength 1260~1650nm). It is aimed to ensure the convenience of operation and maintenance in the future. Reduce the cost of network maintenance and transformation.
(3) Ambient temperature and humidity
To introduce the influence of ambient temperature and humidity on the PLC optical splitter, we take K city as an example. The historical lowest temperature in K City is -26℃, and the highest temperature is 38.5℃. Considering the influence of the geographical environment and installation method on the actual temperature. The working environment temperature of the optical splitter is determined to be -40℃~+85℃.
City K is a coastal area with high relative humidity and high salinity. Considering the above factors. Determine the relative humidity of the working environment of the optical splitter: ≤95% (+40℃).
3. Installation and use of the plug-in optical splitter
The plug-in optical splitter can be installed in the equipment room or the outdoor fiber optic distribution box.
(1) Install the plug-in plc splitter in the computer room
To install a plug-in plc splitter in the equipment room, a plug-in plc splitter frame is required. The slotted optical splitter frame is installed in a 19-inch standard cabinet. Occupying a height of 3U, and can install 17 slotted optical splitters.
(2) Outdoor installation of plug-in optical splitter
To install an optical splitter outdoors, a dedicated distribution box is generally used. The reference size of the 72-core distribution box is 320mm × 420mm × 120mm (width × height × depth). The box body is made of SMC composite material, which is resistant to high and low temperatures and corrosion. It is suitable for various field environments; the front of the box body is sprayed with special signs.
The 72-core distribution box can install 4×1 or 2×2-slot chip-type optical splitters. The interlayer can be flipped over to ensure the bottom fiber splicing operation. The bottom layer has 3 layers of splicing trays and 6 fixed positions for optical cables, which can lead out 72-core pigtails.
The 72-core distribution box can adopt flexible installation methods such as a pole, side support, wall hanging, etc.
Fibconet’s experts focus on the selection principles and technical specifications of FTTH networks. We promise you the following services:
●Low cost.
●Standardized, standardized design and procurement.
●Improve network construction and operation and maintenance efficiency.
